In application Ser. No. 593,385, filed July 7, 1975, now U.S. Pat. No. 4,025,495, issued May 24, 1977, there is recited a process for abating a waste disposal problem in the manufacture of vinyl chloride wherein 1,2 dichloroethane is an intermediate and a heavy residue is recovered as still bottoms, from the purification by distillation of dichloroethane and/or vinyl chloride having an organic-origin chloride content ranging between 55 and 80% by weight, said process comprising reacting said heavy residue at 50.degree. to 100.degree. C., in aqueous medium with an alkali metal or an alkaline earth metal polysulfide, the proportion of polysulfide being equal at least to 30% by weight of the molar theoretical quantity, the average sulfur rank of polysulfide being more than 1 and up to and including 5, the pH of the reaction medium not exceeding 10.5 when the reaction is completed, and the obtained precipitate being separated from the reaction mother liquor, said precipitate being organic polysulfide polymers containing 4-80% by weight of sulfur. After the separation of the precipitate from the mother liquor, it was desirable in many instances for the organic polysulfide polymers to be subjected to a purification stage. It was also desirable in many instances to recover the mineral polysulfides from the aqueous phase.